Technical Field
The present invention relates to semiconductor processing, and more particularly to devices and methods that grow source and drain regions on dielectric materials.
Description of the Related Art
Metal oxide semiconductor field effect transistors (MOSFETs) often suffer from performance loss due to carrier leakage. One of the major leakage sources of MOSFET devices is drain-to-substrate leakage. Here, charge from the drain leaks into the substrate. This is made even more severe when epitaxially grown layers (epilayers) have defects. One method for addressing leakage into the substrate of the device is to provide a buried oxide layer. In a silicon-on-insulator (SOI) structure, a buried oxide layer is disposed between a base (bulk) substrate and a thin silicon layer. The devices are formed in the thin silicon layer, which is isolated from the base substrate by the buried oxide layer. Conventional source and drain regions are single-crystalline so these regions cannot be grown on insulators such as oxide.